CHEK2 and breast carcinoma: For instance, CHEK2 1100delC mutation was frequently observed in some Western and Northern Europe (CHEK2 Breast Cancer Case–control Consortium CHEK2*1100delC and susceptibility to breast cancer 2004), but it was very rare in the Central Europe (Kleibl et al. 2005; Kwiatkowska et al. 2006), Southern Europe (Italy and Spain) (Caligo et al. 2004; Osorio et al. 2004) and Australia (Jekimovs et al. 2005).